As Cesc Fábregas was billeted at London Colney during his team-mates' expedition to Asia on Saturday, the captain's exit from Arsenal took on a sense of inevitability.

However, though Barcelona's courtship of the Catalan will inflict more turmoil on a club supposedly in terminal decline, it should be regarded more as an opportunity than a curse. Even if Fábregas were not pining for his homeland or blighted with frequent hamstring injuries, the time is ripe for his departure.

The World Cup winner is like a one-man Gerrard-Lampard partnership: thrusting, creative and with a threat of goals from midfield. But he, like that pairing, cannot play in the middle of a 4-4-2. Arsène Wenger's pact with Fábregas has been to construct a continental 4-2-3-1, with the little Catalan ghosting around and threading balls between adversaries or lifting passes over defences for forwards to chase. It worked, up to a point. Last season Arsenal were the only team to enjoy on average 60% of the possession – thus they consistently spent 50% more time on the ball than their opponents – while completing more passes than any other.

This comfort with the ball meant Arsenal alone last season were capable of going toe to toe with Barcelona in a meaningful match. However, time has proved the system Fábregas's skills demanded to be ill-suited to English football. When lesser teams arrived at the Emirates they were content to concede all the territory and all the possession, congesting the area around their own goal. Although Arsenal were generating data highly prized by football statisticians – a league-leading 75% of their passes in the final third of the pitch were successful – they could not translate possession into goals. Damagingly, six Premier League teams scored more goals at home than Arsenal last season.

Moreover visitors were playing an Arsenal team that conceded more than half its goals from set pieces, and knew that even by playing ultra-conservatively they could stay in the game. Six teams also lost fewer times at home last season than the Gunners.

With Fábregas in the team Wenger was forced to persevere with the same tactical template: there could be no Plan B of an open and counterattacking 4-4-2. Now, provided he receives a fair price for the only player in the world capable of improving Barcelona's midfield, Wenger is entirely reconciled to losing his captain and will not seek to replace him. Instead Wenger is showing signs that the continental experiment will be discarded in favour of England's atavistic 4-4-2.

Fábregas's sale should generate £35m for Arsenal. If Samir Nasri's departure is reluctantly sanctioned – Wenger does not wish to lose a player whose shooting accuracy is the Premier League's best – it will add £22m more. Although Gervinho's arrival cost £11m, that was offset by the £7m received from Gaël Clichy's departure.

The £53m net transfer income would all be used to strengthen the first team, and across a number of areas. Reports linking Stewart Downing with a £15m move to the Emirates Stadium are entirely plausible. His ability to cross the ball has no replica at Arsenal and would draw more headed goals from Robin van Persie and Marouane Chamakh, whose dangerous aerial ability has not been greatly exploited at the Emirates.

The goalkeeper Manuel Almunia has not travelled to Asia, and Sunderland's £6m Craig Gordon is viewed as a possible replacement. Stoke City's 35-year-old Thomas Sorensen has also been considered to provide meaningful competition to Wojciech Szczesny in what would be an inexpensive trade, provided the Dane does not extend his contract beyond its current 12 months.

An imposing centre-half is an equally urgent requirement. Gary Cahill and Phil Jagielka are favoured because they, like Downing, would help satisfy Uefa and Premier League requirements for homegrown players. But Per Mertesacker, a 75-times capped, 26-year-old Germany international, excites Wenger due to his leadership qualities and his seven-figure price. Take note that Nicklas Bendtner, another left behind as his team tour Asia, is highly regarded at Mertesacker's Werder Bremen and could be used in a swap deal.

Arsenal may have lost out to Juventus in their pursuit of Bayer Leverkusen's £15m Chile international midfielder, Arturo Vidal. However, it shows Wenger is open to strengthening central midfield despite his faith in Emmanuel Frimpong, who must recover from the knee ligament injury he suffered last season.

That leaves the centre-forward position, and the £27m link with Real Madrid's Karim Benzema should not be dismissed. The 23-year-old was off-colour for much of last season, with only one goal in his first 18 La Liga appearances. But with 15 goals in his last 17 starts he proved what a decisive player he still is.

And so Gordon, Downing, Vidal, Gervinho, Mertesacker and Benzema could arrive at a £10m net cost following the departures of Fábregas, Nasri, Clichy and Bendtner. If Wenger can achieve this within his club's existing wage structure – by moving on a number of fringe players – he will have been true to his word as a "very active" manager this summer. Arsenal's spine would be stronger and they would be more of a goal threat. But for all these benefits, with Fábregas gone, the biggest asset Wenger would have added to his side is tactical flexibility.